The equivariant cohomology for semidirect product actions
arXiv:2009.08526
Abstract
The rational Borel equivariant cohomology for actions of a compact connected Lie group is determined by restriction of the action to a maximal torus. We show that a similar reduction holds for any compact Lie group when there is a closed subgroup such that the cohomology of the classifying space is free over the cohomology of for field coefficients. We study the particular case when is a semi-direct product and is its maximal elementary abelian 2-subgroup for cohomology with coefficients in a field of characteristic two. This provides a different approach to investigate the syzygy order of the equivariant cohomology of a space with a torus action and a compatible involution, and we relate this description with results for 2-torus actions.